Right now we have a special case: https://github.com/wikimedia/puppet/blob/486fd8839ac87758dbc5bdb87cf467ac46f8df59/hieradata/role/common/cache/text.yaml#L74-L76 where thumb.php requests are served by image scalers.
I think it should be fairly easy to send those requests to Thumbor instead. Thumbor just needs to parse thumb.php URLs like it does upload.wikimedia.org URLs
Additionally, we need to make sure that Thumbor has the necessary rights to read originals and write thumbnails for private wiki Swift containers.